What are the four main routes to spontaneous premature labor as identified by the March of Dimes?

The identification of infections, maternal stress, bleeding, and uterine overdistention as the four main routes to spontaneous premature labor aligns with established guidelines and research from maternal and neonatal health organizations like the March of Dimes.

Infections can lead to inflammation and an increased release of prostaglandins, which may trigger labor. Maternal stress, whether physical or psychological, can also influence hormonal changes, potentially contributing to early contractions. Bleeding, particularly in the second or third trimester, can be an indicator of problems that may precipitate preterm labor. Uterine overdistention, often due to multiple gestations or excessive amniotic fluid, puts additional stress on the uterine muscles, potentially leading to contractions.

The other options include potential factors that may have some correlation with labor but do not encapsulate the primary recognized triggers as effectively. For instance, dehydration does have an impact on uterine activity, but it is not specifically listed among the main routes recognized by maternal health organizations. Each of the elements in the correct answer is supported by extensive research in obstetric care and is critical for understanding the risks associated with preterm labor.